A spectrum measuring apparatuses, commercialization of which has been considered in recent years, recognizes a measuring object existing in ambient environment by using a spectrum sensor for measuring multi-spectrum data including a non-visible light region. When the spectrum measuring apparatus supplies information about a measuring object to a drive assistance device commercialized for vehicles such as automobiles, the drive assistance device can recognize pedestrians and other vehicles present in the surrounding traffic environment of the vehicle. Then, the drive assistance device can assist driving operation and decision making for the driver.
From the viewpoint of improving the accuracy of recognizing a measuring object (sensing target), it is desired that both spatial resolution and wavelength resolution of spectrum data measured by such spectrum measuring apparatus be high, or fine. However, when both spatial resolution and wavelength resolution are high, the amount of spectrum data may excessively increase. That is, to transfer a large amount of spectrum data, the spectrum measuring apparatus has to have a high data transfer capability and a high data processing capability. Particularly, since the spectrum measuring apparatus mounted in a movable body such as an automobile is strictly restricted in terms of various factors such as design and costs, it is not necessarily practical to achieve a high data transfer capability and a high data processing capability.
For example, a spectrum measuring apparatus described in Patent Document 1 switches between multi-spectrum observation for roughly setting wavelength resolution in place of finely setting spatial resolution and hyper-spectrum observation for roughly setting spatial resolution in place of finely setting wavelength resolution.
In the document, the spectrum measuring apparatus sets the wavelength resolution and spatial resolution to values corresponding to multi-spectrum observation or values corresponding to hyper spectrum observation, for example, by binning of collectively read data for each pixel received by a detector formed of a two-dimensional CCD in a vertical or horizontal direction. Such switching between multi-spectrum observation and hyper-spectrum observation actually changes the amount of spectrum data. That is, the amount of spectrum data observed by the spectrum measuring apparatus is changed as necessary and the amount of spectrum data read by the detector is reduced as necessary.